Paul F Worley

Johns Hopkins University, Baltimore, Maryland, United States

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Publications (254)2401.63 Total impact

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    ABSTRACT: Arc is a cellular immediate-early gene (IEG) that functions at excitatory synapses and is required for learning and memory. We report crystal structures of Arc subdomains that form a bi-lobar architecture remarkably similar to the capsid domain of human immunodeficiency virus (HIV) gag protein. Analysis indicates Arc originated from the Ty3/Gypsy retrotransposon family and was "domesticated" in higher vertebrates for synaptic functions. The Arc N-terminal lobe evolved a unique hydrophobic pocket that mediates intermolecular binding with synaptic proteins as resolved in complexes with TARPγ2 (Stargazin) and CaMKII peptides and is essential for Arc's synaptic function. A consensus sequence for Arc binding identifies several additional partners that include genes implicated in schizophrenia. Arc N-lobe binding is inhibited by small chemicals suggesting Arc's synaptic action may be druggable. These studies reveal the remarkable evolutionary origin of Arc and provide a structural basis for understanding Arc's contribution to neural plasticity and disease. Copyright © 2015 Elsevier Inc. All rights reserved.
    Neuron 04/2015; DOI:10.1016/j.neuron.2015.03.030 · 15.98 Impact Factor
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    ABSTRACT: Circuit computation requires precision in the timing, extent, and synchrony of principal cell (PC) firing that is largely enforced by parvalbumin-expressing, fast-spiking interneurons (PVFSIs). To reliably coordinate network activity, PVFSIs exhibit specialized synaptic and membrane properties that promote efficient afferent recruitment such as expression of high-conductance, rapidly gating, GluA4-containing AMPA receptors (AMPARs). We found that PVFSIs upregulate GluA4 during the second postnatal week coincident with increases in the AMPAR clustering proteins NPTX2 and NPTXR. Moreover, GluA4 is dramatically reduced in NPTX2(-/-)/NPTXR(-/-) mice with consequent reductions in PVFSI AMPAR function. Early postnatal NPTX2(-/-)/NPTXR(-/-) mice exhibit delayed circuit maturation with a prolonged critical period permissive for giant depolarizing potentials. Juvenile NPTX2(-/-)/NPTXR(-/-) mice display reduced feedforward inhibition yielding a circuit deficient in rhythmogenesis and prone to epileptiform discharges. Our findings demonstrate an essential role for NPTXs in controlling network dynamics highlighting potential therapeutic targets for disorders with inhibition/excitation imbalances such as schizophrenia. Copyright © 2015 Elsevier Inc. All rights reserved.
    Neuron 03/2015; 85(6). DOI:10.1016/j.neuron.2015.02.020 · 15.98 Impact Factor
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    ABSTRACT: Protein kinase C epsilon (PKCε) is emerging as a potential target for the development of pharmacotherapies to treat alcohol use disorders, yet little is known regarding how a history of a highly prevalent form of drinking, binge alcohol intake, influences enzyme priming or the functional relevance of kinase activity for excessive alcohol intake. Immunoblotting was employed on tissue from subregions of the nucleus accumbens (NAc) and the amygdala to examine both idiopathic and binge drinking-induced changes in constitutive PKCε priming. The functional relevance of PKCε translocation for binge drinking and determination of potential upstream signaling pathways involved were investigated using neuropharmacologic approaches within the context of two distinct binge drinking procedures, drinking in the dark and scheduled high alcohol consumption. Binge alcohol drinking elevated p(Ser729)-PKCε levels in both the NAc and the central nucleus of the amygdala (CeA). Moreover, immunoblotting studies of selectively bred and transgenic mouse lines revealed a positive correlation between the propensity to binge drink alcohol and constitutive p(Ser729)-PKCε levels in the NAc and CeA. Finally, neuropharmacologic inhibition of PKCε translocation within both regions reduced binge alcohol consumption in a manner requiring intact group 1 metabotropic glutamate receptors, Homer2, phospholipase C, and/or phosphotidylinositide-3 kinase function. Taken together, these data indicate that PKCε signaling in both the NAc and CeA is a major contributor to binge alcohol drinking and to the genetic propensity to consume excessive amounts of alcohol. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
    Biological psychiatry 03/2015; DOI:10.1016/j.biopsych.2015.01.019 · 9.47 Impact Factor
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    ABSTRACT: Rheb, a ubiquitous small GTPase, is well known to bind and activate mTOR, which augments protein synthesis. Inhibition of protein synthesis is also physiologically regulated. Thus, with cell stress, the unfolded protein response system leads to phosphorylation of the initiation factor eIF2α and arrest of protein synthesis. We now demonstrate a major role for Rheb in inhibiting protein synthesis by enhancing the phosphorylation of eIF2α by protein kinase-like ER kinase (PERK). Interplay between the stimulatory and inhibitory roles of Rheb may enable cells to modulate protein synthesis in response to varying environmental stresses. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Cell Reports 02/2015; DOI:10.1016/j.celrep.2015.01.014 · 7.21 Impact Factor
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    ABSTRACT: In Parkinson's disease, long-term dopamine replacement therapy is complicated by the appearance of l-DOPA-induced dyskinesia (LID). One major hypothesis is that LID results from an aberrant transcriptional program in striatal neurons induced by l-DOPA and triggered by the activation of ERK. To identify these genes, we performed transcriptome analyses in the striatum in 6-hydroxydopamine-lesioned mice. A time course analysis (0-6 h after treatment with l-DOPA) identified an acute signature of 709 genes, among which genes involved in protein phosphatase activity were overrepresented, suggesting a negative feedback on ERK activation by l-DOPA. l-DOPA-dependent deregulation of 28 genes was blocked by pretreatment with SL327, an inhibitor of ERK activation, and 26 genes were found differentially expressed between highly and weakly dyskinetic animals after treatment with l-DOPA. The intersection list identified five genes: FosB, Th, Nptx2, Nedd4l, and Ccrn4l. Nptx2 encodes neuronal pentraxin II (or neuronal activity-regulated pentraxin, Narp), which is involved in the clustering of glutamate receptors. We confirmed increased Nptx2 expression after l-DOPA and its blockade by SL327 using quantitative RT-PCR in independent experiments. Using an escalating l-DOPA dose protocol, LID severity was decreased in Narp knock-out mice compared with their wild-type littermates or after overexpression of a dominant-negative form of Narp in the striatum. In conclusion, we have identified a molecular signature induced by l-DOPA in the dopamine-denervated striatum that is dependent on ERK and associated with LID. Here, we demonstrate the implication of one of these genes, Nptx2, in the development of LID. Copyright © 2015 the authors 0270-6474/15/350096-16$15.00/0.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 01/2015; 35(1):96-111. DOI:10.1523/JNEUROSCI.5231-13.2015 · 6.75 Impact Factor
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    ABSTRACT: Activation of the Notch pathway in neurons is essential for learning and memory in various species from invertebrates to mammals. However, it remains unclear how Notch signaling regulates neuronal plasticity, and whether the transcriptional regulator and canonical pathway effector RBP-J plays a role. Here we report that conditional disruption of RBP-J in the postnatal hippocampus leads to defects in long-term potentiation (LTP), long-term depression (LTD), and in learning and memory. Using gene expression profiling and chromatin immunoprecipitation, we identified two GABA transporters, GAT2 and BGT1, as putative Notch/RBP-J pathway targets, which may function downstream of RBP-J to limit the accumulation of GABA in the Schaffer collateral pathway. Our results reveal an essential role for canonical Notch/RBP-J signaling in hippocampal synaptic plasticity and suggest that role, at least in part, is mediated by the regulation of GABAergic signaling. This article is protected by copyright. All rights reserved.
    Hippocampus 12/2014; 25(5). DOI:10.1002/hipo.22402 · 4.30 Impact Factor
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    ABSTRACT: Rheb1 is an immediate early gene that functions to activate mammalian target of rapamycin (mTor) selectively in complex 1 (mTORC1). We have demonstrated previously that Rheb1 is essential for myelination in the CNS using a Nestin-Cre driver line that deletes Rheb1 in all neural cell lineages, and recent studies using oligodendrocyte-specific CNP-Cre have suggested a preferential role for mTORC1 is myelination in the spinal cord. Here, we examine the role of Rheb1/mTORC1 in mouse oligodendrocyte lineage using separate Cre drivers for oligodendrocyte progenitor cells (OPCs) including Olig1-Cre and Olig2-Cre as well as differentiated and mature oligodendrocytes including CNP-Cre and Tmem10-Cre. Deletion of Rheb1 in OPCs impairs their differentiation to mature oligodendrocytes. This is accompanied by reduced OPC cell-cycle exit suggesting a requirement for Rheb1 in OPC differentiation. The effect of Rheb1 on OPC differentiation is mediated by mTor since Olig1-Cre deletion of mTor phenocopies Olig1-Cre Rheb1 deletion. Deletion of Rheb1 in mature oligodendrocytes, in contrast, does not disrupt developmental myelination or myelin maintenance. Loss of Rheb1 in OPCs or neural progenitors does not affect astrocyte formation in gray and white matter, as indicated by the pan-astrocyte marker Aldh1L1. We conclude that OPC-intrinsic mTORC1 activity mediated by Rheb1 is critical for differentiation of OPCs to mature oligodendrocytes, but that mature oligodendrocytes do not require Rheb1 to make myelin or maintain it in the adult brain. These studies reveal mechanisms that may be relevant for both developmental myelination and impaired remyelination in myelin disease. Copyright © 2014 the authors 0270-6474/14/3415764-15$15.00/0.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 11/2014; 34(47):15764-78. DOI:10.1523/JNEUROSCI.2267-14.2014 · 6.75 Impact Factor
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    ABSTRACT: Production of reactive oxygen species (ROS) increases with neuronal activity that accompanies synaptic development and function. Transcription-related factors and metabolic enzymes that are expressed in all tissues have been described to counteract neuronal ROS to prevent oxidative damage. Here, we describe the antioxidant gene LanCL1 that is prominently enriched in brain neurons. Its expression is developmentally regulated and induced by neuronal activity, neurotrophic factors implicated in neuronal plasticity and survival, and oxidative stress. Genetic deletion of LanCL1 causes enhanced accumulation of ROS in brain, as well as development-related lipid, protein, and DNA damage; mitochondrial dysfunction; and apoptotic neurodegeneration. LanCL1 transgene protects neurons from ROS. LanCL1 protein purified from eukaryotic cells catalyzes the formation of thioether products similar to glutathione S-transferase. These studies reveal a neuron-specific glutathione defense mechanism that is essential for neuronal function and survival.
    Developmental Cell 08/2014; 30(4):479-487. DOI:10.1016/j.devcel.2014.06.011 · 10.37 Impact Factor
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    ABSTRACT: Neuronal activity regulated pentraxin (Narp) is a secreted protein implicated in regulating synaptic plasticity via its association with the extracellular surface of AMPA receptors. We found robust Narp immunostaining in dorsal root ganglia (DRG) that is largely restricted to small diameter neurons, and in the superficial layers of the dorsal horn of the spinal cord. In double staining studies of DRG, we found that Narp is expressed in both IB4- and CGRP-positive neurons, markers of distinct populations of nociceptive neurons. Although a panel of standard pain behavioral assays were unaffected by Narp deletion, we found that Narp knockout mice displayed an exaggerated microglia/macrophage response in the dorsal horn of the spinal cord to sciatic nerve transection 3days after surgery compared with wild type mice. As other members of the pentraxin family have been implicated in regulating innate immunity, these findings suggest that Narp, and perhaps other neuronal pentraxins, also regulate inflammation in the nervous system.
    Journal of Neuroimmunology 06/2014; 274(1-2). DOI:10.1016/j.jneuroim.2014.06.016 · 2.79 Impact Factor
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    Paul Worley, Marshall Shuler
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    ABSTRACT: The word "memory" is derived from the ancient Greek myth of Mnemosyne, the mother of the Muses, who was "said to know everything, past, present, and future." Memory is essential to our existence, and one of neuroscience's primary missions is to understand how the brain processes memory and to improve treatments for Alzheimer's disease, traumatic brain injury, drug addiction, and the many other afflictions associated with disrupted memory. Our article traces scientists' progress in understanding memory over the last 15 years.
    Cerebrum: the Dana forum on brain science 01/2014; 2014:2.
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    ABSTRACT: The Shank3 gene encodes a scaffolding protein that anchors multiple elements of the postsynaptic density at the synapse. Previous attempts to delete the Shank3 gene have not resulted in a complete loss of the predominant naturally occurring Shank3 isoforms. We have now characterized a homozygous Shank3 mutation in mice that deletes exon 21, including the Homer binding domain. In the homozygous state, deletion of exon 21 results in loss of the major naturally occurring Shank3 protein bands detected by C-terminal and N-terminal antibodies, allowing us to more definitively examine the role of Shank3 in synaptic function and behavior. This loss of Shank3 leads to an increased localization of mGluR5 to both synaptosome and postsynaptic density-enriched fractions in the hippocampus. These mice exhibit a decrease in NMDA/AMPA excitatory postsynaptic current ratio in area CA1 of the hippocampus, reduced long-term potentiation in area CA1, and deficits in hippocampus-dependent spatial learning and memory. In addition, these mice also exhibit motor-coordination deficits, hypersensitivity to heat, novelty avoidance, altered locomotor response to novelty, and minimal social abnormalities. These data suggest that Shank3 isoforms are required for normal synaptic transmission/plasticity in the hippocampus, as well as hippocampus-dependent spatial learning and memory.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 11/2013; 33(47):18448-18468. DOI:10.1523/JNEUROSCI.3017-13.2013 · 6.75 Impact Factor
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    ABSTRACT: Down syndrome (DS) is among the most frequent genetic causes of intellectual disability, and ameliorating this deficit is a major goal in support of people with trisomy 21. The Ts65Dn mouse recapitulates some major brain structural and behavioral phenotypes of DS, including reduced size and cellularity of the cerebellum and learning deficits associated with the hippocampus. We show that a single treatment of newborn mice with the Sonic hedgehog pathway agonist SAG 1.1 (SAG) results in normal cerebellar morphology in adults. Further, SAG treatment at birth rescued phenotypes associated with hippocampal deficits that occur in untreated adult Ts65Dn mice. This treatment resulted in behavioral improvements and normalized performance in the Morris water maze task for learning and memory. SAG treatment also produced physiological effects and partially rescued both N-methyl-d-aspartate (NMDA) receptor-dependent synaptic plasticity and NMDA/AMPA receptor ratio, physiological measures associated with memory. These outcomes confirm an important role for the hedgehog pathway in cerebellar development and raise the possibility for its direct influence in hippocampal function. The positive results from this approach suggest a possible direction for therapeutic intervention to improve cognitive function for this population.
    Science translational medicine 09/2013; 5(201):201ra120. DOI:10.1126/scitranslmed.3005983 · 14.41 Impact Factor
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    ABSTRACT: Despite the fact that binge alcohol drinking (intake resulting in blood alcohol concentrations80 mg% within a 2-h period) is the most prevalent form of alcohol use disorders (AUD), a large knowledge gap exists regarding how this form of AUD impacts neural circuits mediating alcohol reinforcement. The present study employed integrative approaches to examine the functional relevance of binge drinking-induced changes in glutamate receptors, their associated scaffolding, and certain signaling molecules within the central nucleus of the amygdala (CeA). A 30-day history of binge alcohol drinking (eg, 4-5 g/kg/2-h) elevated CeA levels of mGluR1, GluN2B, Homer2a/b, and phospholipase C (PLC) β3, without significantly altering protein expression within the adjacent basolateral amygdala. An intra-CeA infusion of mGluR1, mGluR5 and PLC inhibitors all dose-dependently reduced binge intake, without influencing sucrose drinking. The effects of co-infusing mGluR1 and PLC inhibitors were additive, while those of co-inhibiting mGluR5 and PLC were not, indicating that the efficacy of mGluR1 blockade to lower binge intake involves a pathway independent of PLC activation. The efficacy of mGluR1, mGluR5 and PLC inhibitors to reduce binge intake depended upon intact Homer2 expression as revealed through neuropharmacological studies of Homer2 null mutant mice. Collectively, these data indicate binge alcohol-induced increases in Group1 mGluR signaling within the CeA as a neuroadaptation maintaining excessive alcohol intake, which may contribute to the propensity to binge drink.Neuropsychopharmacology accepted article preview online, 21 August 2013. doi:10.1038/npp.2013.214.
    Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology 08/2013; 39(2). DOI:10.1038/npp.2013.214 · 7.83 Impact Factor
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    ABSTRACT: Synaptic plasticity induced by cocaine and other drugs underlies addiction. Here we elucidate molecular events at synapses that cause this plasticity and the resulting behavioral response to cocaine in mice. In response to D1-dopamine-receptor signaling that is induced by drug administration, the glutamate-receptor protein metabotropic glutamate receptor 5 (mGluR5) is phosphorylated by microtubule-associated protein kinase (MAPK), which we show potentiates Pin1-mediated prolyl-isomerization of mGluR5 in instances where the product of an activity-dependent gene, Homer1a, is present to enable Pin1-mGluR5 interaction. These biochemical events potentiate N-methyl-D-aspartate receptor (NMDAR)-mediated currents that underlie synaptic plasticity and cocaine-evoked motor sensitization as tested in mice with relevant mutations. The findings elucidate how a coincidence of signals from the nucleus and the synapse can render mGluR5 accessible to activation with consequences for drug-induced dopamine responses and point to depotentiation at corticostriatal synapses as a possible therapeutic target for treating addiction.
    Cell 08/2013; 154(3):637-50. DOI:10.1016/j.cell.2013.07.001 · 33.12 Impact Factor
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    ABSTRACT: The immediate early gene neuronal activity-regulated pentraxin (NARP) is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) binding protein that is specifically enriched at excitatory synapses onto fast-spiking parvalbumin-positive interneurons (FS [PV] INs). Here, we show that transgenic deletion of NARP decreases the number of excitatory synaptic inputs onto FS (PV) INs and reduces net excitatory synaptic drive onto FS (PV) INs. Accordingly, the visual cortex of NARP(-/-) mice is hyperexcitable and unable to express ocular dominance plasticity, although many aspects of visual function are unimpaired. Importantly, the number and strength of inhibitory synaptic contacts from FS (PV) INs onto principle neurons in the visual cortex is normal in NARP(-/-) mice, and enhancement of this output recovers the expression of experience-dependent synaptic plasticity. Thus the recruitment of inhibition from FS (PV) INs plays a central role in enabling the critical period for ocular dominance plasticity.
    Neuron 07/2013; 79(2):335-46. DOI:10.1016/j.neuron.2013.05.016 · 15.98 Impact Factor
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    ABSTRACT: Pain alters opioid reinforcement, presumably via neuroadaptations within ascending pain pathways interacting with the limbic system. Nerve injury increases expression of glutamate receptors and their associated Homer scaffolding proteins throughout the pain processing pathway. Homer proteins, and their associated glutamate receptors, regulate behavioral sensitivity to various addictive drugs. Thus, we investigated a potential role for Homers in the interactions between pain and drug reward in mice. Chronic constriction injury (CCI) of the sciatic nerve elevated Homer1b/c and/or Homer2a/b expression within all mesolimbic structures examined and for the most part, the Homer increases coincided with elevated mGluR5, GluN2A/B, and the activational state of various down-stream kinases. Behaviorally, CCI mice showed pain hypersensitivity and a conditioned place-aversion (CPA) at a low heroin dose that supported conditioned place-preference (CPP) in naïve controls. Null mutations of Homer1a, Homer1, and Homer2, as well as transgenic disruption of mGluR5-Homer interactions, either attenuated or completely blocked low-dose heroin CPP, and none of the CCI mutant strains exhibited heroin-induced CPA. However, heroin CPP did not depend upon full Homer1c expression within the nucleus accumbens (NAC), as CPP occurred in controls infused locally with small hairpin RNA-Homer1c, although intra-NAC and/or intrathecal cDNA-Homer1c, -Homer1a, and -Homer2b infusions (to best mimic CCI's effects) were sufficient to blunt heroin CPP in uninjured mice. However, arguing against a simple role for CCI-induced increases in either spinal or NAC Homer expression for heroin CPA, cDNA infusion of our various cDNA constructs either did not affect (intrathecal) or attenuated (NAC) heroin CPA. Together, these data implicate increases in glutamate receptor/Homer/kinase activity within limbic structures, perhaps outside the NAC, as possibly critical for switching the incentive motivational properties of heroin following nerve injury, which has relevance for opioid psychopharmacology in individuals suffering from neuropathic pain.
    Frontiers in Psychiatry 06/2013; 4:39. DOI:10.3389/fpsyt.2013.00039
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    ABSTRACT: Synaptic long-term potentiation (LTP) is a key mechanism involved in learning and memory, and its alteration is associated with mental disorders. Shank3 is a major postsynaptic scaffolding protein that orchestrates dendritic spine morphogenesis, and mutations of this protein lead to mental retardation and autism spectrum disorders. In the present study we investigated the role of a new Shank3-associated protein in LTP. We identified the Rho-GAP interacting CIP4 homolog 2 (Rich2) as a new Shank3 partner by proteomic screen. Using single-cell bioluminescence resonance energy transfer microscopy, we found that Rich2-Shank3 interaction is increased in dendritic spines of mouse cultured hippocampal neurons during LTP. We further characterized Rich2 as an endosomal recycling protein that controls AMPA receptor GluA1 subunit exocytosis and spine morphology. Knock-down of Rich2 with siRNA, or disruption of the Rich2-Shank3 complex using an interfering mimetic peptide, inhibited the dendritic spine enlargement and the increase in GluA1 subunit exocytosis typical of LTP. These results identify Rich2-Shank3 as a new postsynaptic protein complex involved in synaptic plasticity.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 06/2013; 33(23):9699-9715. DOI:10.1523/JNEUROSCI.2725-12.2013 · 6.75 Impact Factor
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    ABSTRACT: While group 1 metabotropic glutamate receptors (mGluRs) and ionotropic N-methyl-D-aspartate (NMDA) receptors regulate nociception, the precise molecular mechanism(s) contributing to glutamate signaling in chronic pain remain unclear. Here we not only confirmed the key involvement of Homer proteins in neuropathic pain, but also distinguished between the functional roles for different Homer family members and isoforms. Chronic constriction injury (CCI) of the sciatic nerve induced long-lasting, time-dependent increases in the postsynaptic density expression of the constitutively expressed (CC) isoforms Homer1b/c and/or Homer2a/b in the spinal dorsal horn and supraspinal structures involved in nociception (prefrontal cortex, thalamus), that co-occurred with increases in their associated mGluRs, NR2 sub-units of the NMDA receptor, and the activation of downstream kinases. Virus-mediated overexpression of Homer1c and Homer2b after spinal (intrathecal) virus injection exacerbated CCI-induced mechanical and cold hypersensitivity, however, Homer1 and Homer2 gene knockout (KO) mice displayed no changes in their neuropathic phenotype. In contrast, overexpression of the immediate early gene (IEG) Homer1a isoform reduced, while KO of Homer1a gene potentiated neuropathic pain hypersensitivity. Thus, nerve injury-induced increases in CC-Homers expression promote pain in pathological states, but IEG-Homer induction protects against both the development and maintenance of neuropathy. Additionally, exacerbated pain hypersensitivity in transgenic mice with reduced Homer binding to mGluR5 supports also an inhibitory role for Homer interactions with mGluR5 in mediating neuropathy. Such data indicate that nerve injury-induced changes in glutamate receptor/Homer signaling contribute in dynamic but distinct ways to neuropathic pain processing, which has relevance for the etiology of chronic pain symptoms and its treatment.
    Pain 04/2013; 154(10). DOI:10.1016/j.pain.2013.03.035 · 5.84 Impact Factor
  • Cell 01/2013; 152(1-2):367. DOI:10.1016/j.cell.2012.12.039 · 33.12 Impact Factor
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    ABSTRACT: BACKGROUND AND PURPOSE: Motor recovery after ischemic stroke in primary motor cortex is thought to occur in part through training-enhanced reorganization in undamaged premotor areas, enabled by reductions in cortical inhibition. Here we used a mouse model of focal cortical stroke and a double lesion approach to test the idea that a medial premotor area (medial agranular cortex [AGm]) reorganizes to mediate recovery of prehension, and that this reorganization is associated with a reduction in inhibitory interneuron markers. METHODS: C57Bl/6 mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent photocoagulation-induced stroke in the caudal forelimb area. The mice were then retrained and inhibitory interneuron immunofluorescence was assessed in prechosen, anatomically defined neocortical areas. Mice then underwent a second photocoagulation-induced stroke in AGm. RESULTS: Focal caudal forelimb area stroke led to a decrement in skilled prehension. Training-associated recovery of prehension was associated with a reduction in parvalbumin, calretinin, and calbindin expression in AGm. Subsequent infarction of AGm led to reinstatement of the original deficit. CONCLUSIONS: We conclude that with training, AGm can reorganize after a focal motor stroke and serve as a new control area for prehension. Reduced inhibition may represent a marker for reorganization or it is necessary for reorganization to occur. Our mouse model, with all of the attendant genetic benefits, may allow us to determine at the cellular and molecular levels how behavioral training and endogenous plasticity interact to mediate recovery.
    Stroke 01/2013; 44(2). DOI:10.1161/STROKEAHA.112.676940 · 6.02 Impact Factor

Publication Stats

28k Citations
2,401.63 Total Impact Points


  • 1987–2015
    • Johns Hopkins University
      • • Department of Neuroscience
      • • Department of Neurology
      Baltimore, Maryland, United States
  • 1989–2012
    • Johns Hopkins Medicine
      • Department of Neuroscience
      Baltimore, Maryland, United States
  • 2007–2010
    • University of Texas Southwestern Medical Center
      • Department of Physiology
      Dallas, TX, United States
    • Molecular and Cellular Biology Program
      Seattle, Washington, United States
  • 2009
    • University of North Carolina at Chapel Hill
      North Carolina, United States
  • 1988–2006
    • University of Maryland, Baltimore
      • Department of Pharmacology
      Baltimore, Maryland, United States
  • 2005
    • University of Milan
      Milano, Lombardy, Italy
  • 2001
    • University of California, Irvine
      • Department of Anatomy and Neurobiology
      Irvine, California, United States
  • 1999
    • Yamagata University
      Ямагата, Yamagata, Japan
  • 1998
    • University of Virginia
      • Department of Neuroscience
      Charlottesville, Virginia, United States
  • 1988–1998
    • Howard Hughes Medical Institute
      Ashburn, Virginia, United States
  • 1994
    • The University of Arizona
      • Department of Psychology
      Tucson, AZ, United States